Views: 0 Author: Site Editor Publish Time: 2026-06-04 Origin: Site
Six mainstream flanges including WN, SO, BL, SW, TH, LJ dominate global piping projects under ASME B16.5 & EN 1092-1 standards. Wrong structure selection always causes extra procurement cost and hidden safety risk, detailed specification as below:
WN Weld Neck Flange: Tapered long hub with full penetration butt weld, max rating up to Class2500, excellent thermal & pressure resistance, widely applied in refinery, power plant and critical flammable fluid pipeline with higher cost.
SO Slip On Flange: Pipe slides into flange bore with double fillet weld, cost-effective & easy installation from Class150 to Class300, top choice for water supply, HVAC and general low-moderate pressure chemical piping, most popular in global market.
BL Blind Flange: Solid blank disc for pipe end closure & future expansion, available for all pressure classes, essential spare part for every engineering project maintenance.
SW Socket Weld Flange: For small bore DN≤80 only, pipe inserted into counterbore then welded, better tightness than SO, Class300~600 standard for instrument and small high-pressure gas piping.
TH Threaded NPT Flange: No welding needed with internal NPT thread, perfect for explosion-proof gas pipeline construction, not suitable for cyclic high temperature service.
LJ Lap Joint Flange: Split design with stub end + loose backing flange, rotatable flange for easy bolt hole alignment. Users can use expensive stainless steel stub end & cheap carbon steel flange to cut cost on corrosive medium piping with frequent disassembly requirement.
Quick selection rule: WN for critical high-pressure service; SO for general low-pressure project; BL for end blocking; SW for small bore high-pressure; TH for non-weld explosion-proof; LJ for corrosive frequent-maintenance piping. We are China OEM flange forging factory for non-standard customized sizes.
